More than 99% of Email is Spam?

One of my pet peeves is the headline "n %" of email is spam, it is inherently misleading, and conveys no useful data. I guess it makes for great newspaper headlines then! On our servers looking at one email address for 4 hours, we saw 208 attempted connections for SMTP traffic referring to this email address. ...One can't measure spam in relation to the amount of genuine email, because the amount of genuine email is not connected to the amount of spam... more

False Positives and Ignorance

Content inspection is a poor way to recognise spam, and the proliferation of image spam recently drums this home. However if one must use these unreliable techniques, one should bring mathematical rigour to the procedure. Tools like SpamAssassin combine content inspection results, with other tests, in order to tune rule-sets to give acceptable rates of false positives (mistaking genuine emails for spam), and thus end up assigning suitable weights to different content rules. If one is going to use these approaches to filtering spam, and some see it as inevitable, one better know one's statistics... more

There Is No “Spam Problem”

This month I thought I could feel smug, deploying Postfix, with greylisting (Postgrey), and the Spamhaus block list (SBL-XBL) has reduced the volume of unsolicited bulk commercial email one of our servers was delivering to our clients by 98.99%. Alas greylisting is a flawed remedy, it merely requires the spambots to act more like email servers and it will fail, and eventually they will... more

Have You Monitored Your DNS Performance Lately?

Domain Name System (DNS) surveys such as that recently conducted by Men & Mice continually demonstrate that the DNS is riddled with errors. Since the DNS continues to work, this raises three questions:

1. Does it matter that the DNS is riddled with errors?
2. Why is it riddled with errors?
3. How can it be fixed? more